Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C17/00—Preparation of halogenated hydrocarbons
  • C07C17/093—Preparation of halogenated hydrocarbons by replacement by halogens
  • C07C17/15—Preparation of halogenated hydrocarbons by replacement by halogens with oxygen as auxiliary reagent, e.g. oxychlorination
  • C07C17/152—Preparation of halogenated hydrocarbons by replacement by halogens with oxygen as auxiliary reagent, e.g. oxychlorination of hydrocarbons
  • C07C17/156—Preparation of halogenated hydrocarbons by replacement by halogens with oxygen as auxiliary reagent, e.g. oxychlorination of hydrocarbons of unsaturated hydrocarbons

Definitions

• the present invention relates to a method and an apparatus for producing 1, 2-dichloroethane by reacting ethene with hydrogen chloride and a gas containing oxygen in a fluidized bed oxichlorination reactor, whereby a reaction gas is formed.
• Oxychlorination means the reaction of an alkene - here ethene - with hydrogen chloride and oxygen or an oxygen-containing gas such as air, with the formation of a saturated chlorinated alkane - here 1,2-dichloroethane, also called “EDC” in the following.
• EDC oxygen-containing gas
• reaction by-product water of this reaction can form the very strongly corrosive hydrochloric acid with the unreacted starting material chlorinated hydrocarbon, so that when such a process is carried out, correspondingly resistant - and therefore expensive - materials have to be used for the apparatus for carrying out the process.
• the oxychlorination reaction is carried out in the presence of a catalyst.
• this process serves as a catalyst for In an embodiment often used on a large industrial scale, this process serves as a catalyst for In an embodiment of this process which is frequently used on a large industrial scale, a catalyst fluidized bed which essentially consists of copper chloride on an aluminum oxide support serves as the catalyst for the oxychlorination reaction.
• the catalyst in the top part of the oxychlorination reactor is separated off by a plurality of cyclones connected in series and thus largely retained in the reactor.
• a small proportion of the catalyst, the so-called catalyst abrasion passes into the reaction gas leaving the reactor and thus passes into the 1,2-dichloroethane workup, where it has to be separated off again.
• DE-A-197 53 165 discloses a process for the preparation of 1,2-dichloroethane by oxychlorination, ethene reacting with hydrogen chloride and an oxygen-containing gas in a fluidized bed from a copper-containing catalyst and the reaction gas emerging from the reactor In the reactor, the catalyst is removed by ultra-fine filtration and is thus retained in the reactor. Thereafter, the reaction gas freed from the catalyst is passed into a column and condensed in a known manner.
• a disadvantage of this method is the accumulation of the very fine particles in the reactor through the filtration. This is associated with a deterioration in the flow properties of the catalyst bed and a deterioration in the heat transfer in the reactor. Furthermore is under! others due to the lack of pre-separation by the reactor cyclones, the dust loading of the reaction gas is very high. This high particle content means that the filter area has to be increased significantly. Furthermore, the method described in DE 197 53 165 can only be applied to existing systems with complex means, so that this method will only be used in new systems and is hardly an option for existing systems.
• reaction gas is filtered outside the oxychlorination reactor by means of at least one filter candle.
• the at least one filter candle has as filter material at least one ceramic material and / or at least one sintered metal powder, and / or at least one wire fleece made of stainless steel (1.4571 or equivalent materials) or another suitable alloy.
• Alloys such as are commercially available under the designation ⁇ INCONEL, ⁇ MONEL and / or ⁇ HASTELLOY, can be used for this purpose, for which at least one filter candle is used.
• Filter candles which have ceramic materials of corresponding medium pore sizes can also be used.
• the filter materials can have, for example, average pore sizeix from 0.0001 to ⁇ 5 ⁇ m. If, on the other hand, fabric filters are used, the So far they have been regarded as having the same effect, so no separation of dioxins / furans can be achieved.
• reaction gases are additionally subjected to direct condensation, i.e. subjected to condensation without quenching, the small amounts of PCDD or PCDF that may still be present enter the organic phase almost quantitatively and the wastewater from the oxychlorination is largely free of these substances.
• the problem of settling of the very fine particles in and thus clogging of the filter housing could be solved by the following flow guidance of the gas in the filter:
• the resulting velocity vector directed in the direction of gravity from the sinking velocity of the catalyst particles and the flow velocity of the gas is greater than 0.
• reaction gas it is even conceivable in certain applications for the reaction gas to be condensed directly after a very fine filtration without prior quenching, so that the previously always necessary in the prior art Quenching process step can be omitted.
• a device can thus be used in which no so-called quench tower is necessary, which results in a space saving in the device to be used.
• the process conditions in particular those of the oxychlorination step using a fluidized bed, can preferably be carried out in accordance with the process conditions described in German Patent Specification 1,518,931 and German Patent 1,468,489, the disclosure of which is hereby incorporated by reference into the present description.
• the reaction gas After leaving the oxychlorination reactor in a process according to the invention, the reaction gas preferably flows through the filter candle at a pressure of about 1 to 6 bar, preferably of about 3.5 bar.
• the reaction gas should have a temperature of about 200 to 250 ° C, preferably about 220 ° C when flowing through the filter.
• the proportion of polychlorinated dibenzo-p-dioxins / furans (PCDD / PCDF) in 1,2-dichloroethane by a process according to the invention is preferably less than 0.1 ⁇ g / to 1.2 dichloroetha.
• the degree of separation of the entrained catalyst particles in the oxychlorination process using a fluidized bed in a process according to the invention in accordance with a preferred embodiment is more than 99.99%.
• the filtration is carried out with a filter candle located outside the oxychlorination reactor for carrying out a process according to the invention, it is very easy to retrofit existing oxychlorination plants with a fluidized bed. This can be done very easily, in particular because the filters used can be built very compactly with at least one filter candle. Due to the high operational reliability of the filter cartridges, it is also possible to do without a reserve unit.
• the filter cartridges are subject to practically no wear, they have an unlimited service life, especially since the particles in the filter cartridge can be easily removed with the current flow according to the invention. This has also proven to be an advantage, since no complex maintenance work has to be carried out.
• the device for producing 1, 2-dichloroethane according to the oxychlorination process in a fluidized bed reactor should have feeds for hydrogen chloride and oxygen-containing gas, which lead directly into the fluidized bed of the oxychlorination reactor.
• These feeds can be formed from porous, gas-permeable moldings.
• the ethene and the circulating gas flow take place in the oxychlorination reactor, which supports the formation of the fluidized bed, via a base which is made of porous, gas-permeable material or is provided with moldings made of porous, gas-permeable material.
• the design of the feed lines could be selected, for example, in the manner described in DE 199 03 335 AI, which is to be included here in the description with reference.
• the single figure shows an example of a device according to the invention in accordance with a preferred embodiment.
• the preheated educts of hydrogen chloride and oxygen are passed directly into a reaction space of a reactor 3 via a pipeline 1.
• the preheated cycle gas and ethene are fed into the reactor 3 via a further pipeline 2.
• the reactor 3 there is a catalyst, which is not shown in the figure.
• the crude 1,2 dichloroethane stream, the process water and the cycle gas are passed through cyclones 4 into the fine filter 6.
• the separated fine catalyst dust is discharged from the system via a lock 7.
• the preheated backwashing gas for cleaning (backwashing) the filter elements is passed into the filter 6 via a third pipeline 5.
• the crude 1,2-dichloroethane stream, the process water and the cycle gas without a significant fine particle fraction are ⁇ further Pipeline 8 passed into a condenser 9, in which the EDC - and the water vapor are condensed.
• the liquid EDC / water mixture is separated from the circulating gas in a separator 10 and is worked up via a pipeline 12.
• the circulating gas is returned via a pipeline 11 to the suction side of the circulating gas compressor.
• An oxychlorination reactor with a fluidized bed is used for the preparation of 1,2-dichloroethane, CuCl 2 being used as the catalyst.
• the oxychlorination is carried out under customary process conditions which are known to the person skilled in the art and are therefore not mentioned explicitly.
• the reaction gas (500 Nm 3 / h) flows through a fine filter of a dry operated cleaning zone at a temperature of 200 to 250 ° C (preferably 220 ° C) and a pressure of about 1 to 6 bar (preferably 3.5 bar) ) for the separation of entrained particles of the catalyst, the so-called catalyst abrasion, whereby the catalyst is practically completely separated.
• the ultra-fine filter consists of 8 filter elements.
• the filter elements are made of 316 S (stainless steel).
• the 8 filter elements are periodically backwashed via automatic valves. Pre-heated nitrogen is used as the backwash gas, which is used at a pressure of 8 1 bar Available.
• the fine dust separated in the filter cone is removed lx / day via a lock.
• reaction gas is guided in such a way that the resulting velocity vector in the direction of gravity from the sinking velocity of the catalyst particles and the flow velocity of the gas (cycle gas, 1,2 dichloroethane and process water) is greater than 0.
• the reaction gas freed from catalyst abrasion at a temperature of 200 to 250 ° C., preferably about 220 ° C., is then fed via a line into a condenser, where the EDC and the production water are condensed.
• the condensed liquid is separated from the circulating gas in a gas separator.
• the EDC / water mixture is fed via a pipe to a separation tank in which the water phase is separated from the EDC.
• PCDD polychlorinated dibenzodioxins
• PCDF polychlorinated dibenzofurans
• the degree of separation of entrained catalyst particles is thus more than 99.99%.
• the content of polychlorinated dibenzo-p-dioxins / furans in the wastewater can be drastically reduced. It is therefore no longer necessary to dispose of the wastewater very costly and time-consuming after the oxychlorination.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
• Filtering Materials (AREA)

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• 2001
  • 2001-02-13 DE DE10107089A patent/DE10107089A1/de not_active Withdrawn
• 2002
  • 2002-02-13 ES ES02701274T patent/ES2289078T3/es not_active Expired - Lifetime
  • 2002-02-13 ZA ZA200305918A patent/ZA200305918B/en unknown
  • 2002-02-13 EP EP02701274A patent/EP1360162B1/de not_active Expired - Lifetime
  • 2002-02-13 PT PT02701274T patent/PT1360162E/pt unknown
  • 2002-02-13 PL PL02364224A patent/PL364224A1/xx unknown
  • 2002-02-13 UA UA2003087627A patent/UA74869C2/uk unknown
  • 2002-02-13 RU RU2003127727/04A patent/RU2304136C2/ru not_active IP Right Cessation
  • 2002-02-13 JP JP2002564472A patent/JP4393067B2/ja not_active Expired - Fee Related
  • 2002-02-13 HU HU0303884A patent/HUP0303884A3/hu unknown
  • 2002-02-13 CN CNB028049004A patent/CN1308274C/zh not_active Expired - Fee Related
  • 2002-02-13 WO PCT/EP2002/001503 patent/WO2002064535A1/de active IP Right Grant
  • 2002-02-13 MX MXPA03007224A patent/MXPA03007224A/es unknown
  • 2002-02-13 CZ CZ20032187A patent/CZ20032187A3/cs unknown
  • 2002-02-13 DE DE50210851T patent/DE50210851D1/de not_active Expired - Lifetime
  • 2002-02-13 KR KR10-2003-7010580A patent/KR20040002864A/ko not_active Application Discontinuation
  • 2002-02-13 AT AT02701274T patent/ATE372312T1/de not_active IP Right Cessation
  • 2002-02-13 US US10/467,599 patent/US20040073073A1/en not_active Abandoned
  • 2002-02-13 BR BR0207177-0A patent/BR0207177A/pt not_active Application Discontinuation
• 2003
  • 2003-07-22 MA MA27248A patent/MA26076A1/fr unknown
  • 2003-08-06 NO NO20033489A patent/NO20033489L/no not_active Application Discontinuation

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